Impact Tools with Torque-Limited Swinging Weight Impact Mechanisms
Illustrative embodiments impact tools with torque-limited swinging weight impact mechanisms are disclosed. In at least one illustrative embodiment, a swinging weight impact mechanism may comprise a hammer configured to rotate about a first axis and pivot about a second axis different from the first axis, the hammer having a void formed therein, and an asymmetric anvil disposed partially within the void, the asymmetric anvil being configured to rotate about a third axis when impacted by the hammer. The asymmetric anvil may comprise a cylindrical body and a lug extending outward from the cylindrical body. The lug may include a first impact face extending along a first plane that intersects the third axis and a second impact face extending along a second plane that does not intersect the third axis, where the second plane intersects the first plane along a line that passes through the cylindrical body of the asymmetric anvil.
The present disclosure relates, generally, to impact tools and, more particularly, to impact tools having torque-limited swinging weight impact mechanisms.
BACKGROUNDAn impact tool (e.g., an impact wrench) may be used to install and remove fasteners. An impact tool generally includes a motor coupled to an impact mechanism that converts torque provided by the motor into a series of powerful rotary blows directed from one or more hammers to an anvil that is integrally formed with (or otherwise coupled to) an output drive of the impact tool. In many impact tools, the impact mechanism is typically configured to deliver the same amount of torque to the output drive when installing the fastener as when removing the fastener.
SUMMARYAccording to one aspect, an impact tool may comprise a swinging weight impact mechanism that comprises a hammer configured to rotate about a first axis and to pivot about a second axis different from the first axis, the hammer having a void formed therein, and an asymmetric anvil disposed partially within the void formed in the hammer, the asymmetric anvil being configured to rotate about a third axis when impacted by the hammer. The asymmetric anvil may comprise a cylindrical body and a lug extending outward from the cylindrical body, where the lug includes (i) a first impact face that extends along a first plane that intersects the third axis and (ii) a second impact face that extends along a second plane that does not intersect the third axis. The second plane may intersect the first plane along a line that passes through the cylindrical body of the asymmetric anvil. In some embodiments, the third axis may be coincident with the first axis.
In some embodiments, the asymmetric anvil is not symmetric about any line that is perpendicular to the third axis and passes through the lug. The lug may extend outward from a first half of the cylindrical body of the asymmetric anvil, and the line at which the first and second planes intersect may pass through a second half of the cylindrical body of the asymmetric anvil that is opposite the first half.
In some embodiments, the first impact face of the lug of the asymmetric anvil may be configured to be impacted by the hammer in response to rotation of the hammer about the first axis in a first direction, and the second impact face of the lug of the asymmetric anvil may be configured to be impacted by the hammer in response to rotation of the hammer about the first axis in a second direction opposite the first direction. The asymmetric anvil may further include an output drive configured to mate with one of a plurality of interchangeable sockets. The first direction may be a counter-clockwise direction, and the second direction may be a clockwise direction.
In some embodiments, the swinging weight impact mechanism may further comprise a hammer frame supporting the hammer for rotation therewith about the first axis, where the hammer is pivotably coupled to the hammer frame via a pivot pin disposed along the second axis. The impact tool may further comprise a motor coupled to the hammer frame and configured to drive rotation of the hammer frame about the first axis. In other embodiments, the impact tool may further comprise a motor coupled to a camming plate of the swinging weight impact mechanism, where the motor is configured to drive rotation of the camming plate about the first axis such that the camming plate drives rotation of the hammer about the first axis.
According to another aspect, an impact tool may comprise a swinging weight impact mechanism that comprises a hammer frame supporting a hammer for rotation therewith about a first axis, the hammer being pivotably coupled to the hammer frame such that the hammer is configured to pivot about a second axis different from the first axis, a camming plate configured to rotate about the first axis to drive rotation of the hammer about the first axis, and an asymmetric anvil configured to rotate about the first axis when impacted by the hammer. The asymmetric anvil may comprise a cylindrical body and a lug extending outward from the cylindrical body. The lug may include (i) a first impact face extending outward from the cylindrical body at a first angle relative to the cylindrical body and (ii) a second impact face extending outward from the cylindrical body at a second angle relative to the cylindrical body, where the second angle is different from the first angle.
In some embodiments, the cylindrical body may have a first radius relative to the first axis, and the lug may have a second radius relative to the first axis, where the second radius is greater than the first radius. The lug may include an outer surface extending between the first and second impact faces. An entirety of the outer surface may have the second radius.
In some embodiments, the first impact face may extend along a first plane that is orthogonal to the cylindrical body, and the second impact face may extend along a second plane that is not orthogonal to the cylindrical body. In some embodiments, the asymmetric anvil is not symmetric about any line that is perpendicular to the first axis and passes through the lug.
According to yet another aspect, an impact tool may comprise a swinging weight impact mechanism that comprises a hammer configured to rotate about a first axis and to pivot about a second axis different from the first axis, the hammer including a first impact face and a second impact face, a camming plate configured to rotate about the first axis to drive rotation of the hammer about the first axis, and an anvil configured to rotate about the first axis when impacted by the hammer, the anvil including a cylindrical body and a lug extending outward from the cylindrical body, the lug including a first impact face and a second impact face. The first impact faces of the hammer and the anvil may be arranged such that a reactionary force resulting from an impact between the first impact faces includes a first force component in a radially outward direction relative to the first axis. The second impact faces of the hammer and the anvil may be arranged such that a reactionary force resulting from an impact between the second impact faces does not include a second force component in a radially outward direction relative to the first axis that is equal in magnitude to or greater in magnitude than the first force component.
In some embodiments, the hammer may be formed to include a void and first and second jaws extending into the void, where the first jaw includes the first impact face of the hammer and the second jaw includes the second impact face of the hammer. The anvil may be disposed partially within the void formed in the hammer. The first impact faces of the hammer and the anvil may be configured to be transverse during an impact between the first impact faces, and the second impact faces of the hammer and the anvil may be configured to be parallel during an impact between the second impact faces.
In some embodiments, the first impact face of the hammer may be configured to impact the first impact face of the anvil in response to rotation of the hammer in a first direction, and the second impact face of the hammer may be configured to impact the second impact face of the anvil in response to rotation of the hammer in a second direction opposite the first direction. The second impact face of the anvil may have a first end adjacent the cylindrical body and a second end adjacent an outer surface of the lug. The second impact face of the hammer may be configured to impact the first end during rotation of the hammer in the second direction. In some embodiments, the anvil may further include an output drive configured to mate with one of a plurality of interchangeable sockets. The first direction may be a counter-clockwise direction, and the second direction may be a clockwise direction.
The concepts described in the present disclosure are illustrated by way of example and not by way of limitation in the accompanying figures. For simplicity and clarity of illustration, elements illustrated in the figures are not necessarily drawn to scale. For example, the dimensions of some elements may be exaggerated relative to other elements for clarity. Further, where considered appropriate, reference labels have been repeated among the figures to indicate corresponding or analogous elements.
While the concepts of the present disclosure are susceptible to various modifications and alternative forms, specific exemplary embodiments thereof have been shown by way of example in the figures and will herein be described in detail. It should be understood, however, that there is no intent to limit the concepts of the present disclosure to the particular forms disclosed, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the present disclosure.
Referring now to
The motor 12 and the impact mechanism 14 are adapted to rotate the output drive 16 in both clockwise and counterclockwise directions (e.g., for tightening and loosening fasteners) about an output axis 20. As illustratively shown in
As described in detail below, the impact mechanism 14 of the impact tool 10 is embodied as a “swinging weight” impact mechanism 14, in which one or more hammers 34 of the impact mechanism 14 each rotate about one axis (e.g., the axis 20 shown in
In some embodiments, the anvil 36 of the impact mechanism 14 may be integrally formed with the output drive 16. In other embodiments, the anvil 36 and the output drive 16 may be formed separately and coupled to one another, such that the output drive 16 is configured to rotate as a result of rotation of the anvil 36. The output drive 16 is configured to mate with one of a plurality of interchangeable sockets 26 (e.g., for use in tightening and loosening fasteners, such as nuts and bolts). Although the output drive 16 is illustratively shown as a square drive 16, the principles of the present disclosure may be applied to an output drive 16 of any suitable size and shape. As shown in
In the illustrative embodiment, the impact mechanism 14 is directly driven by the motor 12. In particular, the rotor 32 of the motor 12 includes a plurality of vanes (not shown) that are configured to be driven by a supply of motive fluid. The rotor 32 is mechanically coupled to one or more components of the impact mechanism 14 (e.g., a camming plate or a hammer frame) via a splined interface 68 (see, for example,
Referring now to
The hammer 34 is supported by the hammer frame 38 for rotation therewith about the axis 20. In particular, the hammer 34 is pivotably coupled to the hammer frame 38 via the pivot pin 42, which is disposed along an axis 74 that is generally parallel to and spaced apart from the axis 20. As will be appreciated from
The anvil 36 includes a cylindrical body 56 and a lug 58 that extends outward from the cylindrical body 56 (i.e., in a radial direction relative to the axis 20). The cylindrical body 56 of the anvil 36 is generally cylindrical in shape but may include sections of varying cross-section. As indicated above, the anvil 36 may be integrally formed with or coupled to the output drive 16 such that rotation of the anvil 36 drives rotation of the output drive 16. The lug 58 of the anvil 36 includes the impact face 60 that is impacted by the impact face 52 of the hammer 34 when the hammer 34 is rotated in a tightening direction 62 (e.g., clockwise from the perspective of the rear end 24 of the impact tool 10). The lug 58 of the anvil 36 also includes the impact face 64 that is impacted by the impact face 54 of the hammer 34 when the hammer 34 is rotated in a loosening direction 66 (e.g., counter-clockwise from the perspective of the rear end 24 of the impact tool 10). An outer surface 80 of the lug 58 extends between the impact faces 52, 54. The configuration of the anvil 36 is described in further detail below with reference to
In the illustrative embodiment, the camming plate 40 is coupled to the rotor 32 of the motor 12 via a splined interface 68 between these components. As best seen in
During operation of the impact tool 10, the motor 12 drives rotation of the camming plate 40 about the axis 20 such that the camming plate 40 drives rotation of the hammer 34 about the axis 20. That is, the camming plate 40 forces the linkage 72 of the hammer 34 in the same direction of rotation, thereby driving rotation of the hammer 34 itself and the pivotally coupled hammer frame 38 about the axis 20. As the hammer 34 rotates about the anvil 36, the lug 58 of the anvil 36 interacts with the interior surface 46 of the hammer 34 to move the hammer 34 into an engaged position (overcoming the radially outward biasing force applied by the camming plate 40). While in the engaged position, the hammer 34 continues to rotate about the anvil 36 until the leading impact face 52, 54 (depending on the direction of rotation) of the hammer 34 impacts the corresponding impact face 60, 64 of the lug 58 of the anvil 36 (as shown, for the rotational direction 62, in
Upon impact, the hammer 34 delivers a torque to the anvil 36 and rebounds from the anvil 36 in a direction opposite the direction of rotation of the hammer 34 prior to impact. By way of example, where the hammer 34 is traveling in the direction 62 prior to impact with the anvil 36, the hammer 34 will rebound in the direction 66 after impact (e.g., during the tightening of a fastener with the impact tool 10). As will be appreciated from the present disclosure, a greater torque may be transferred during an impact of the hammer 34 with the anvil 36 where the hammer 34 has full or direct contact, rather than partial or glancing contact, with the anvil 36. Glancing contact may occur, for example, if the impact face 52 of the hammer 34 and the impact face 60 of the anvil 36 are configured such that only portions of the impact faces 52, 60 contact one another during an impact (as shown in
Upon impact of the hammer 34 and the anvil 36 during operation of the impact mechanism 114, a reactionary force is applied by the anvil 36 to the hammer 34 that causes the rebound of the hammer 34 described above (i.e., this reactionary force tends to separate the leading impact face 52, 54 of the hammer 34 from the corresponding impact face 60, 64 of the anvil 36). Due to the shape of the impact face 60 of the anvil 36 shown in
Referring now to
As can be seen in
In traditional impact mechanisms, the anvil 36 is typically symmetric about a midline 88 that is perpendicular to the axis 20 and passes through the lug 58, such that an angle 90 of a typical impact face 92 (shown in phantom) relative to the midline 88 is equal to an angle 94 of the impact face 64 relative to the midline 88. It should further be appreciated that, in a typical anvil 36 (as just described), a plane 96 coincident with the impact face 92 and a plane 98 coincident with the impact face 64 will oftentimes intersect one another at the axis 20. However, in the illustrative embodiment, the impact face 60 has been modified (relative to the typical impact face 92) such that the anvil 36 is asymmetric. In other words, according to the present disclosure, the anvil 36 is not symmetric about any line that is perpendicular to the axis 20 and passes through the lug 58.
Described in another way, the impact face 64 extends outward from cylindrical body 56 at an angle 94 relative to the midline 88 and coincides with a plane 98 that intersects the axis 20, whereas the impact face 60 extends outward from the cylindrical body 56 at an angle 100 relative to the midline 88 and coincides with a plane 102 that does not intersect the axis 20 (but does intersect the midline 88 at a different point 104). In the illustrative embodiment, the planes 98, 102 (along which the impact faces 64, 60 extend, respectively) intersect one another at a line 106 that passes through the cylindrical body 56 (the line 106 traveling into and out of the page in
Referring now to
Referring now to
Unlike the impact mechanism 114, the illustrative impact mechanism 314 does not include a camming plate. Rather, the hammer frame 38 is coupled directly (or, in some embodiments, via a drive train) to the rotor 32 of the motor 12. As such, rotation of the rotor 32 drives rotation of the hammer frame 38 about the axis 20, which in turn drives rotation of the hammer 34 about the axis 20. As shown in
During operation of the impact mechanism 314, the motor 12 drives rotation of the hammer frame 38, which is pivotally coupled to the hammer 34 by the pivot pin 42. Accordingly, the hammer frame 38 drives rotation of the hammer 34 in the same direction as the direction of rotation of the hammer frame 38. As the hammer 34 rotates about the anvil 36, the leading impact face 52, 54 (depending on the direction of rotation) of the hammer 34 will impact the corresponding impact face 60, 64 of the anvil 36, imparting a torque on the anvil 36 and causing the hammer 34 to rebound (in a manner generally similar to that described above with regard to the impact mechanism 114). As with the impact mechanism 114, the impact face 60 of the anvil 36 of the impact mechanism 314 extends outward from the cylindrical body 56 at a different angle than the impact face 64. As a result, less torque is transferred from the hammer 34 to the anvil 36 as a result of an impact between the impact faces 52, 60 (i.e., when the hammer is rotating in the direction 62) than as a result of an impact between the impact faces 54, 64 (i.e., when the hammer is rotating in the direction 66). Moreover, when the hammer 34 is traveling in the direction 62 prior to impact, a reactionary force on the hammer 34 resulting from an impact between the impact faces 52, 60 will include a force component in a radially outward direction relative to the axis 20 (whereas the reactionary force on the hammer 34 resulting from an impact between the impact faces 54, 64 will not include such a force component).
Referring now to
Furthermore, the operation of the impact mechanism 414 is generally similar to that of the impact mechanism 114. For instance, during operation of an impact tool 10 incorporating the impact mechanism 414, the motor 12 drives rotation of the camming plate 40 via splined interface 68. The camming plate 40, in turn, drives rotation of the hammer 34 via the linkage 72. Upon impact with the anvil 36, the hammer 34 applies a torque to the anvil 36 and rebounds from the anvil 36 in the opposite direction. Additionally, as with the camming plate 40 of the impact mechanism 114, the camming plate 40 of the impact mechanism 414 biases the hammer 34 toward a disengaged position relative to the anvil 36 (e.g., radially outward relative to the axis 20).
As shown in
Referring now to
However, in the illustrative embodiment of the impact mechanism 514 shown in
While certain illustrative embodiments have been described in detail in the figures and the foregoing description, such an illustration and description is to be considered as exemplary and not restrictive in character, it being understood that only illustrative embodiments have been shown and described and that all changes and modifications that come within the spirit of the disclosure are desired to be protected. For example, while the impact mechanism 14 has been illustratively shown and described as including one hammer 34, it will be appreciated that the concepts of the present disclosure might also be applied to impact mechanisms including two or more hammers.
There are a plurality of advantages of the present disclosure arising from the various features of the apparatus, systems, and methods described herein. It will be noted that alternative embodiments of the apparatus, systems, and methods of the present disclosure may not include all of the features described yet still benefit from at least some of the advantages of such features. Those of ordinary skill in the art may readily devise their own implementations of the apparatus, systems, and methods that incorporate one or more of the features of the present disclosure.
Claims
1. An impact tool comprising:
- a swinging weight impact mechanism comprising: a hammer configured to rotate about a first axis and to pivot about a second axis different from the first axis, the hammer having a void formed therein; and an asymmetric anvil disposed partially within the void formed in the hammer, the asymmetric anvil being configured to rotate about a third axis when impacted by the hammer;
- wherein the asymmetric anvil comprises a cylindrical body and a lug extending outward from the cylindrical body, the lug including (i) a first impact face that extends along a first plane that intersects the third axis and (ii) a second impact face that extends along a second plane that does not intersect the third axis, the second plane intersecting the first plane along a line that passes through the cylindrical body of the asymmetric anvil.
2. The impact tool of claim 1, wherein the third axis is coincident with the first axis.
3. The impact tool of claim 1, wherein the asymmetric anvil is not symmetric about any line that is perpendicular to the third axis and passes through the lug.
4. The impact tool of claim 1, wherein:
- the lug extends outward from a first half of the cylindrical body of the asymmetric anvil; and
- the line at which the first and second planes intersect passes through a second half of the cylindrical body of the asymmetric anvil that is opposite the first half.
5. The impact tool of claim 1, wherein:
- the first impact face of the lug of the asymmetric anvil is configured to be impacted by the hammer in response to rotation of the hammer about the first axis in a first direction; and
- the second impact face of the lug of the asymmetric anvil is configured to be impacted by the hammer in response to rotation of the hammer about the first axis in a second direction opposite the first direction.
6. The impact tool of claim 5, wherein the asymmetric anvil further includes an output drive configured to mate with one of a plurality of interchangeable sockets, the first direction being a counter-clockwise direction and the second direction being a clockwise direction.
7. The impact tool of claim 1, wherein the swinging weight impact mechanism further comprises a hammer frame supporting the hammer for rotation therewith about the first axis, the hammer being pivotably coupled to the hammer frame via a pivot pin disposed along the second axis.
8. The impact tool of claim 7, further comprising a motor coupled to the hammer frame and configured to drive rotation of the hammer frame about the first axis.
9. The impact tool of claim 7, further comprising a motor coupled to a camming plate of the swinging weight impact mechanism, the motor being configured to drive rotation of the camming plate about the first axis such that the camming plate drives rotation of the hammer about the first axis.
10. An impact tool comprising:
- a swinging weight impact mechanism comprising: a hammer frame supporting a hammer for rotation therewith about a first axis, the hammer being pivotably coupled to the hammer frame such that the hammer is configured to pivot about a second axis different from the first axis; a camming plate configured to rotate about the first axis to drive rotation of the hammer about the first axis; and an asymmetric anvil configured to rotate about the first axis when impacted by the hammer, the asymmetric anvil comprising a cylindrical body and a lug extending outward from the cylindrical body, the lug including (i) a first impact face extending outward from the cylindrical body at a first angle relative to the cylindrical body and (ii) a second impact face extending outward from the cylindrical body at a second angle relative to the cylindrical body, the second angle being different from the first angle.
11. The impact tool of claim 10, wherein the cylindrical body has a first radius relative to the first axis and the lug has a second radius relative to the first axis, the second radius being greater than the first radius.
12. The impact tool of claim 11, wherein the lug includes an outer surface extending between the first and second impact faces, an entirety of the outer surface having the second radius.
13. The impact tool of claim 10, wherein:
- the first impact face extends along a first plane that is orthogonal to the cylindrical body; and
- the second impact face extends along a second plane that is not orthogonal to the cylindrical body.
14. The impact tool of claim 10, wherein the asymmetric anvil is not symmetric about any line that is perpendicular to the first axis and passes through the lug.
15. An impact tool comprising:
- a swinging weight impact mechanism comprising: a hammer configured to rotate about a first axis and to pivot about a second axis different from the first axis, the hammer including a first impact face and a second impact face; a camming plate configured to rotate about the first axis to drive rotation of the hammer about the first axis; and an anvil configured to rotate about the first axis when impacted by the hammer, the anvil including a cylindrical body and a lug extending outward from the cylindrical body, the lug including a first impact face and a second impact face;
- wherein the first impact faces of the hammer and the anvil are arranged such that a reactionary force resulting from an impact between the first impact faces includes a first force component in a radially outward direction relative to the first axis; and
- wherein the second impact faces of the hammer and the anvil are arranged such that a reactionary force resulting from an impact between the second impact faces does not include a second force component in a radially outward direction relative to the first axis that is equal in magnitude to or greater in magnitude than the first force component.
16. The impact tool of claim 15, wherein:
- the hammer is formed to include a void and first and second jaws extending into the void, the first jaw including the first impact face of the hammer and the second jaw including the second impact face of the hammer; and
- the anvil is disposed partially within the void formed in the hammer.
17. The impact tool of claim 15, wherein:
- the first impact faces of the hammer and the anvil are configured to be transverse during an impact between the first impact faces; and
- the second impact faces of the hammer and the anvil are configured to be parallel during an impact between the second impact faces.
18. The impact tool of claim 15, wherein:
- the first impact face of the hammer is configured to impact the first impact face of the anvil in response to rotation of the hammer in a first direction; and
- the second impact face of the hammer is configured to impact the second impact face of the anvil in response to rotation of the hammer in a second direction opposite the first direction.
19. The impact tool of claim 18, wherein the second impact face of the anvil has a first end adjacent the cylindrical body and a second end adjacent an outer surface of the lug, the second impact face of the hammer being configured to impact the first end during rotation of the hammer in the second direction.
20. The impact tool of claim 18, wherein the anvil further includes an output drive configured to mate with one of a plurality of interchangeable sockets, the first direction being a counter-clockwise direction and the second direction being a clockwise direction.
Type: Application
Filed: Feb 14, 2014
Publication Date: Aug 20, 2015
Patent Grant number: 9737978
Inventors: Hunter Ian Golden (Apex, NC), Timothy Richard Cooper (Titusville, NJ), Evan Dalton Gerber (Bethlehem, PA), Nicholas J. Able (Huntersville, NC)
Application Number: 14/181,205